Blood Brain Barrier Flashcards
What are the protective features of the brain? (4)
- Skull and vertebral column
- The meninges (protective membranes)
- Cerebrospinal fluid (cushioning)
- Blood brain barrier (highly selective)
What are the three membranes that make up the meninges?
- Dura mater
- Arachnoid mater
- Pia mater
What are the 2 main extracellular fluid compartments in the brain?
- CSF compartment
- The interstitial compartment
How many ventricles are there in the brain?
4
What cells line the ventricles in the brain?
Ciliated ependymal cells
Where is cerebrospinal fluid (CSF) made?
It is synthesised by the epithelial cells of the choroid plexuses in the ventricles of the brain.
What is the route of drainage of CSF from the brain?
It drains into the subarachnoid space then via the arachnoid villi into the dural sinus
What is the blood brain barrier?
A highly regulated barrier between the blood and the interstitial fluid of the brain.
What are the physical features of brain capillaries? (3)
- Cerebral microvascular endothelial cells have tight junctions
- Pericytes
- Astrocyte foot processes surround the capillary.
What MUST drugs pass through in order to reach the brain?
The endothelial cell that makes up the wall of the brain capillary.
What are the 3 routes of drug absorption across the BBB?
- Transcellular lipophilic pathway
- Carrier mediated transport
- Receptor mediated transcytosis
What features must a drug have to cross the BBB via lipid mediated transport? (3)
- Small (< 400 MW)
- Highly lipid soluble (high LogP, low H bonding- less than 7)
- Low polar surface area (<70 A squared)
What receptor transports glucose across the BBB?
GLUT 1
What are the 5 carrier mediated transporters of the BBB?
- GLUT1
- LAT1
- CAT1
- MCT1
- CNT2
What carrier mediated transporter does L-dopa have a strong affinity for and why?
LAT1 because L-dopa is a large neutral amino acid.
